In an LTE-based mobile communication system, a user equipment UE in an RRC idle state measures received qualities (Reference Signal Received Power (RSRP)/Reference Signal Received Quality (RSRQ)) of signals which are transmitted from a base station eNB of a serving cell and a base station eNB of an adjacent cell, and performs cell selection or cell reselection on the basis of the measurement result (for example, see Non-Patent Document 1).
A user equipment UE in an RRC connected state measures received quality of signals which are transmitted from a base station eNB of a serving cell and a base station eNB of an adjacent cell and broadcasts the measurement result as a measurement report to the base stations eNB, and the base stations eNB control, for example, a handover on the basis of the measurement report (for example, see Non-Patent Document 2).